There’s a trillion ones around unrealism, so I may as well pick something that would be more enjoyable if fixed.
Professional chatter. Let’s say a team of 30 scientists have been trying to communicate with a dimensional portal for 5 years. They wouldn’t be using speech like “Identity verified. Doctor Faris, you are clear to approach the anomaly.” Often, they’d have extremely abbreviated lingo for everything they need to express that happens on a daily basis, and otherwise are chatting about other stuff.
“Ok, approach endorsed. Bob wasn’t so chatty yesterday from what I heard, we’ll just aim for 2 logic points for this cycle.”
“Ryan was suggesting we spread the cycles. Bob has to sleep sometime.”
“Yeah, 90% of us would rather listen to Ryan than Mick, but Mick signs the checks.”
So the only actual order comes from some obscure phrase like “Approach endorsed”, which they may only say verbatim for safety reasons. The rest is just workplace banter about how best to accomplish their task, none of it being essential. EDIT: And, to make clear, in the above quote, Bob is the portal/anomaly.
In Robocop when Murphy gets shot to pieces and wheeled into the ER, Verhoeven got real ER doctors to play the scene, so their chatter is very realistic and very nonchalant as they work on a guy that they know full-well is a lost cause.
There’s normally one unrealistic conceit, eg aliens existing, that the audience believes. But then, the regular conceits like “The scientists studying the aliens speak like a bunch of robots and act like total idiots” become harder to believe.
This is what makes Arrival so good. They don't want the best person for the job because she insists on being involved, they give the aliens nicknames immediately and everything goes to shit at the first excuse to start a war.
Oh okay! And I see your edit that Bob is the portal, yeah I did not pick up on that one from the script alone. Great dialog on second pass though! Very believable, Tarantino levels of mundane.